Sprint has announced that beginning today, Samsung Galaxy Mega and Samsung Galaxy S4 Mini customers will be the first Sprint customers to have access to the service after installing an over-the-air update. Here's more info:

Wi-Fi Calling is a FREE service that lets customers use their voice and messaging services over existing home, office and public Wi-Fi networks. With Wi-Fi Calling, our customers will experience improved voice, data and messaging services in locations that previously had limited or no mobile network coverage.

Customer benefits include:-Enhanced coverage for in-building coverage or areas with challenging network conditions.-Easy Setup: Once activated, everything is seamless and happens in the background.-Unlimited voice calling and messaging on Wi-Fi: All domestic calling and messaging is FREE (standard CDMA international rates apply for international calls).

Galaxy Mega and Galaxy S 4 Mini customers will be the first customers to have access to the service after installing an over-the-air update. The update notification will be pushed automatically to these customers during the next few weeks.